First published in 1928, The Secret Teachings of All Ages by Manly P. Hall stands as one of the great reference works of twentieth-century occult and esoteric literature. Monumental in both scope and ambition, the book draws together centuries of philosophy, mythology, symbolism, religion and secret tradition in an attempt to trace the ideas Hall believed lay behind the mystery schools and initiatory traditions of the ancient world.

Its full original title, An Encyclopedic Outline of Masonic, Hermetic, Qabbalistic and Rosicrucian Symbolical Philosophy, gives some indication of the scale of Hall's undertaking. Written while Hall was still in his twenties, the work was conceived not simply as a study of occultism, but as a broad survey of the philosophical and symbolic systems through which different cultures attempted to understand humanity, nature and the divine.

Across the work, Hall investigates the religious and philosophical traditions of ancient Egypt and Greece, the teachings attributed to Hermes Trismegistus, Pythagorean philosophy, the Qabbalah, Rosicrucianism, Freemasonry, alchemy, Tarot, astrology, ceremonial magic and the mystery religions of the ancient world. Alongside these subjects appear discussions of sacred geometry, magical alphabets, secret societies, symbolic architecture, initiation, mythology and the hidden meanings Hall identified within religious imagery.

Rather than treating these traditions as entirely separate subjects, Hall searches for recurring ideas and symbols that appear across different cultures and periods. Myths, initiation rites, sacred numbers, religious allegories, philosophical systems and occult symbols are examined as fragments of what Hall regarded as a much older philosophical tradition. The result is less a conventional history than an immense map of esoteric thought, connecting traditions that are often studied in isolation.

Symbolism lies at the heart of the book. Hall devotes considerable attention to the meaning of the serpent, the cross, the sun, the zodiac, the elements, the human body and countless other images found throughout religion and occult philosophy. He argues that many ancient myths and religious stories can be read on several levels, with their outward narratives concealing philosophical, astronomical or initiatory meanings intended for those able to interpret them.

The original work was also remarkable for its visual presentation. Elaborate illustrations, diagrams, symbolic plates and reproductions accompany Hall's discussions, allowing the reader to examine many of the traditions he describes rather than encountering them through text alone. These images have become an important part of the identity of The Secret Teachings of All Ages and remain integral to understanding the extraordinary breadth of Hall's project.

Nearly a century after its publication, the book continues to serve as an entry point into the history of Western esotericism. It is at once an encyclopedia of occult symbolism, a survey of ancient philosophy and mythology, and a record of Hall's attempt to uncover the connections he believed existed between some of humanity's oldest religious and philosophical traditions. For readers interested in alchemy, Hermeticism, Freemasonry, comparative religion, symbolism or the occult, few single volumes attempt anything on quite the same scale.